More than one platform, different arch/ABI qualify as cross-platform, it is not stated as omni-platform... Zig CC (LLVM backed) is widely used across for materializing first-class C modules. It aims to leverage the Lua ecosystem then it is expected to rely on GNU tools for building legacy, already upstream and stablished LuaRocks packages, i.e. makefiles, or GCC dependent recipes. That is a pragmatic compatibility choice to use the existing Lua ecosystem out-of-the-box, while it is encouraged the use of moonstone native hermetic recipes (which rely on zig cc).